Coling of pistons and piston rods



H. H. BLACHE.

COOLING 0F PISTONS AND PISTON RODS.

APPLICATION FILED FEB. I4. 1922.

jmnggf, mme@ Apr. I8, w22.

NETE@ STATES enfreint ernten,

-EANS lil n "f 1 BLACKS," 0F HELLMUP, NEAR COPENHAGEN; DWK.

CGDLING 0F PISTNS AND JPESTON RODS.

Specicationof Letters Patent.

Patenten een te. rena,

Application ledrliebruary 14,1922. Serial' No. 536,561.

hagen, Denmark,.have invented certain new s and useful ImprovementsRelating to the Cooling of Pistons and Piston -fRods, vof which thefollowing is a specifcatlon.

rllhis invention relates to internal combustion engines and morepartlcularly to double-acting internal combustion-engines of the type inwhich a hollow piston 1s cooled b the circulation of oilor other coolingmedium through the piston rod and hollow piston, the oil being suppliedto the piston` rod through the crosshead from a port or ports in thecrosshead guide. v

Heretofore it has lbeen proposed to provide the crosshead with inlet andoutlet channels, communicating with corresponding ports in the crossheadguide. ln suchcase the channels in the crosshead must be of such alength as to uncover the ports in the lcrosshead guide during the fullstroke of the piston in order to ensure the uninterrupted supply andescape of the coolingpmedium, which is supplied to the engine vunderpressure. t

The object of the present invention is to create the circulation of thecooling -medium through the piston and piston rod by the acceleratingand retarding action of the moving parts and without the necessity ofsupplying the cooling medium under pressure, which is ordinarilynecessary in order to overcome the accelerating and retarding action onthe cooling medium.

According to the present invention the crosshead only uncovers the portor ports in the crosshead guide during more or less of the outer part ofits stroke, so that the said port or ports are only open 4for admissionof the cooling medium to the piston during the louter part of the strokeof the piston, the outlet being open the whole stroke. By this meanslthe acceleration and retardation of the parts creates a circulation 'ofthe oil through the piston and piston rod.

Tn order that the invention may be more clearly understood, reference ishereinafter made to the accompanying drawing showing one construction ofthe cooling means by way of example. v

Fig. 1 is a longitudinal section showing a double-acting internalcombustion engine and Fig. 2 is a corresponding view showing the piston,piston rod and crosshead removed from the en ine. Figs. 3 and 4 show amodified form with a valve placed 4in the supply-pipe.

rlhe crosshead a is connected to the piston rod b which carries apiston, the latter being preferably made in two parts', an outer hollowpart c and an inner hollow part d. The inner part d of the piston isprovided with a tubular extension or sleeve e which surrounds the pistonrod b and entends from the piston beyond a stuffing box f into e thecrank-housing z. The sleeve e does not transmit the thrust of the pistonto the crosshead a2 but loosely surrounds the piston rod b,form1ng anannular chamber m around the piston rod. rllhe sleeve c is of'such alength that its inner end is situated within the enclosed crank housingz' even when the piston is at the end of its out stroke, i. e. in theposition shown in Fig. 1. The sleeve e is formed at its inner endwith aHange g which forms a tight iit with the piston rod, and the sleeve e isalso provided near the fiange g withv a plurality of holes hconnecttition which is provided with a pipe 7c of suitable` lengthextending into the outer part c of the piston and thereby forming aconnection between theV inner and outer chambers of the piston. Anextension of the sleeve e within thehollow part d? of the piston7provides a channel or channels Z opening laterally into the innerchamber of the piston and thus connecting the latter with the interiorof the enclosed crank casina- 'llhe cooling medium is supplied throu hav pipe a which opens into a port a in t e crosshead guide, thecrosshead a being pro-l vided witha recess or channel o adapted toregister with the port n. The channel 0 does not extend the whole len hof the crosshead, but is only'of such a ength that the supply pipe n' isuncovered during more or less of the outer part of the stroke of thepiston i. e. from the position of the piston shown in F ig. 1 half theway or less than half the lway of the stroke before and after thisposition. The channel o communicates by way of a pipe p with a centralbore y in the piston rod b in such a manner that the cooling medium issup-plied by the channel o to the outrjchamber c of the piston..

The arrangement is such that when the crosshead a is in the positionnearest the engine cylinder, it uncovers the supply pipe i reaches themiddle of its stroke.

When the piston is reciprocating between its' middle position and topdead centre, the direction of the retarding .and accelerating forces,which act on the coolino medium within the piston and piston rord; *willbe that indicated by the arrow A in Fig. 1, and in consequence thereofthe cooling-oil will collect as shown at 7' and s (Fig. 2) within thepiston and extend along the annular chamber m to such a level as thatindicated by the letter t in Fig. 2.

During this period the cooling medium will fio-w through the pipe fromthe inner chamber d to the outer chamber 0 of the piston. As soon as thepiston has passed the middle of its stroke and is reciprocating betweenits middle position and the bottom dead centre, the acceleratinoq andretarding forces on the cooling-oil will act in the opposite directionto the arrow A. During this period the supply pipe n for the cooling-oilis cut off from the channel 0 in the crosshead, thereby preventing theback flow of the cooling medium into the supply pipe n. The coolingmedium may, however, flow from the outer chamber c of the piston intothe inner chamber d through the pipe 7c, and from the chamber d throughthe ducts Z into the annular chamber m, and from thence through theopenings h into the enclosed crank housing. The warm cooling medium willtherefore be ejected from the annular chamber m, but a suiiicientquantity will be left in the piston owing to the length of the pipe cand owing to the fact that the ducts Z are disposed at adistance fromthe transverse partition separating the chambers c and d. Every time thepiston reciprocates through the outer part of its stroke, fresh coolingmedium will be suppliedy through the pipe n, and when the piston isreciprocat- 4 ing .through the inner part of its stroke, a proportionalquantit of warm cooling meium will be ejecte through the annular chamberm into'the enclosed crank housing. A suitable quantity of cooling liquidwill always be retained in the two chambers of thepiston, and on accountof the reciprocatory motion, this cooling medium will always be inviolent motion and will thus be splashed upon the hot walls of thepiston.

It is necessary that the crosshead shoe, if the engine ,is to be usedfor a long stroke, should be of considerable length, as the crossheadshoe in all its positions must cover the supply-opening 'n' for thecooling medium.

Misses Such an elongated crosshead shoe necessitates increased firstcost in the manufacturing, besides which the engines will be ofincreased length and weight. The modified form shown in Figs. 3 and 4does away with the above mentioned drawback by the use of a cross-headshoe of normal len-gth, whereas there is arranged in the supp-ly pipefor the cooling medium al cut-off device, for instance a rotating valve,which is driven from the shaft of the engine by means of a chain or'thelike.

In Figs.- 3 and 4 is shown a constructional form. Fig. 3 shows alongitudinal section through the crosshead and the guide planes forsame. Fig. 4 shows a section through the valve placed in the supplypipe.

In the drawing 1 designatesl the cross head shown in the positionnearest to the crank shaft, 2 shows the crosshead in the dead pointposition nearest the cylinder. o designates the recess in the crossheadshoe a and n is the supply pipe for the cooling medium. In the position2 for the crosshead, the supply port o communicates with the" recess owhich through thepipe p is connected to the boring g in the pistonrod bin the manner set forth. The crosshead shoe a has, as shown in thedrawing, such a length that the cross-head shoe covers the port c, whenthe crosshead moves away from the cylinder, somewhat over the middlepart of the stroke.

Between the supply pipe n and the part o is placed a cylindrical casing.fr containing the rotating valve y and said valve is provided with anopening .c which is adapted to register with the port o. The valve isactuated by means of its stem u, which eX- tends through thevalve-casing and is provided with a sprocket wheel w, to be drlven bymeans of a chain from the engine shaft, in such a manner that the valvemakes the same number of revolutions as said shaft. T'he opening a inthe valve is made of a suitable length to enable it to be open to supplythe oil during that part of the stroke where the crosshead shoe with itsoil-channel o covers the supply port o, while the rotating valve shutsoff the port o before the crosshead shoe uncovers said port.

1 claim:

1. An internal combustion engine, comprising a hollow piston havinginner and outer internal chambers, and a transverse partitiontherebetween, a cylinder wherein the piston works; a hollow piston rodconnected to said piston and opening at one end of its bore into theouter piston chamber; and means for supplying a cooling liquid to theother end of the piston rod bore for passage therethrough and throughsaid outer chamber, said partition having means for enabling the passageof the cooling liquid therethrough from one chamber to. the otheralternatelydn lopposite direcfor supplying a cooling liquid to the otherend of the piston bore for passage there; through into the outerchamber; the inner chamber having an outlet for the liquid;

and a tube extendingvfrom the outer chamber through the partition intothe inner chamber to deliver the liquid from one chamber to the otheralternately in opposite directions, said tube having that a quantity ofthe liquid is always retained in the outery chamber. v

3. An internal combustion engine, coinprising a hollow piston havinginner and outer internal chambers,4 and a transverse.

. partition between them; a hollow piston rod connected tothe piston andopening at one end ot its bore into the outer chamber; a cylinderwherein the 'piston works; means for supplying a cooling liquid'to Vtheother a length suchv end of the piston` bore for passage therethroughinto the outer chamber; and a tube extending from the outer chamberthrough the partition into the inner chamber to deliver the liquid fromone chamber to the other alternately in opposite directions, the

inner chamber having a plurality of outlet ports for the liquidv whichare spaced from said partition to insure a quantity of 'said liquidalways being retained in that chamber.

4l. An internal combustion engine', comprising a hollow piston; acylinder wherein the piston works; a crosshead connected to the piston;a crosshead guide provided with an inletport; a delivery pipecommunicating at one end with the interior of the hollow piston andopening at the other end through the crosshead to be' brought into andout of communication witlisaid port; a supply pipe leading to said portf for supplying a cooling medium thereto;

and a rotary cut-0H valve associated with the supply pipe and adapted toautomatically shut O' the flow of the cooling medium when the head, f y

lln testimony whereof ll ailix mysignature.

i HANS l-lE-NRIK BLACHE.

port is uncovered bythe cross-

